The invention is based on a fuel injection pump as generically defined hereinafter.
A major problem in fuel injection pumps of this type, typically embodied as multi-cylinder pumps having a number of pump elements, is the precise orientation of the various control slides, when these slides are adjusted in common by the torque shaft in order to vary the instant of injection or the injection quantity. Even slight differences in the adjustment of the various control slides upon actuation by the torque shaft can lead to considerable error in the control of injection onset of injection quantity, which can cause rough engine operation or deviations from the intended rpm.
Such differences may be due solely to a variable axial play of the individual slide shoes on the individual cylindrical studs. Depending on the play and on the rotational position of the torque shaft, the slide shoe can assume either its outermost or its innermost position, which permits the axial play; the linear contact between the slide shoe and the corresponding limiting surface of the cross groove of the control slide is present both farther inward and farther outward, so that the effective lever arm between this contact line and the axis of the torque shaft exhibits corresponding uncontrolled variations among the various adjusting elements which can lead to the above-mentioned error.
A desired reduction in the axial play must not, however, be allowed to reduce the rotational play of the guide shoe on the cylindrical stud. Only with this rotational play is a linear contact possible when the adjusting force is transmitted from the torque shaft to the control slide. Only by means of the linear force transmission can wear be diminished and the quality of control maintained even over long periods of operation.